The Van Borselen Filters P-SRF sterile air filter candles are depth filters made of a borosilicate glass fiber filter medium. The inner and outer support jacket and end caps are made of stainless steel. The separation rate is 99.99998% based on 0.01 µm. The three-dimensional depth medium has an empty volume of 99%, which results in a high dirt holding capacity with a low differential pressure as well as a high flow rate. Depth filters are recommended as sterile filters for the food industry. They are usually installed locally, the closer to the point of use, the better. We recommend a prior central compressed air treatment with particulate and activated carbon filters and adsorption drying. These filter elements can be sterilized. Sterilization can be done in-line with steam or in an autoclave. Sterilization temperatures vary between 110° and 140° degrees Celsius depending on the duration.